Air charger for hydropneumatic systems



June 19, 195] w, BURKS 2,557,724

AIR CHARGER FOR HYDROPNEUMATIC SYSTEMS Original Filed March 9, 1945'UIIID I EL 2155 Patented June 19, 1951 AIR CHARGER FOR HY DROPNEUMATICSYSTEMS Arthur W. Burks, Decatur,

Ill., assignor to Decatur Pump Company, Decatur, 111., a, corporation ofIllinois Original application March 9, 1945, Serial No.

581,829. Divided and this application April 28, 1949, Serial No. 90,066

6 Claims.

The present invention relates to an air charger for hydro-pneumaticsystems, and more particularly to an air charger for supplying air to ahydro-pneumatic tank in response to the pneumatic pressure requirementsof the system.

This application is a division of my earlier filed copending UnitedStates application for patent, Serial No. 581,829, filed March 9, 1945,now U. S. Patent No. 2,509,130, issued May 23, 1950.

The present invention relates to a novel and improved air chargermechanism for maintaining the pneumatic pressures in a hydro-pneumaticsupply tank within the desired limits. The air charger of my inventionoperates to supply air to the hydro-pneumatic tank if required wheneverthe pump that supplies the hydro-pneumatic tank with water is operated.

An important feature of my invention is the provision of a Venturi-typeeductor, or aspirator,

operated by a flow of water under pressure from the pump, when the aircushion in the tank re-- quires replenishing, to draw atmospheric airinto the air charger casing for subsequent displacement into thehydro-pneumatic tank to replace losses of air from the tank and to buildup the air pressure therein to within the desired limits. A float valvecooperates with the eductor, or aspirator, to eliminate, or at leastreduce, the possibility of air drawn in by the eductor finding its wayinto the pump and causing the pump to become air bound. This has beenone of the objections to previous hydro-pneumatic systems employingmeans, such as an eductor, aspirator, or Venturi nozzle, to draw airinto the system under the action of the pump.

The air charger of my invention acts each time that the pump is startedup, if the water level in the hydro-pneumatic tank is below its normallevel, to introduce a charge of air into the tank. If no air is requiredin the hydropneumatic tank, no new charge of air is delivered into thetank, but air is merely withdrawn from the tank and expelled backthereinto. The device is thus full automatic and requires little, ifany, attention.

It is, therefore, an important object of this invention to provide anautomatically operating air charger for maintaining the desiredpneumatic pressure Within a hydro-pneumatic tank of a water supplysystem, the air charger being responsive to the pumping operation whenthe level of the Water in the tank is above normal to introduce a chargeof air into the hydro-pneumatic tank. The air charger includes aVenturitype eductor, or aspirator, for aspirating air into the systemand a float controlled valve on the suction side of the pump foreliminating or reducing the possibility of such air being drawn into thepump to thereby lessen its efficiency.

It is a further important, object of this invention to provide an aircharger, the operation of which depends upon the action of an eductor,or aspirator, actuated by the pressure discharge of water from the pump,in combination with a float controlled valve on the suction side of thepump to reduce the possibility of air getting back into the suction lineand destroying the prime of the pump.

It is a still further important object of this invention to provide anair charger which, in addition to its function of maintaining thedesired pneumatic pressure in a hydro-pneumatic tank, is so arranged andpositioned as to serve as a prime for the pump, supplying thehydro-pneumatic tank. 7

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawmgs.

On the drawings the single figure is a fragmentary, broken sectionalview partly in elevation, of an air charger embodying the principles Iof my invention.

As shown on the drawing:

The reference numeral I0 refers generally to a hydro-pneumatic tank,which, as is customary, is partially filled with water maintained underthe pressure of an air cushion above the water level. Water is suppliedto the hydro-pneumatic tank ID by a pump ll, preferably of thecentrifugal type, which is connected through a suction intake pipe l2leading through a foot valve I3 and a strainer I 4 to a water supplypipe [5. The pump II is directly connected to the bottom of the tank l0through a discharge pipe [6,

An air charger indicated generally by the reference numeral I1 isconnected by a pipe l8 to the pump discharge l6 through a fitting I9,which is in controlled communication through a port 20 with the intakeside of the pump above the foot valve l3. Said air charger I1 is alsoconnected at its top by means of a pipe 2| through a check valve fitting22 to the tank In at or about its normal water level, as indicated bythe dot-dash line N. The fitting 22 is provided with an enlarged bore 23opening at its inner end into the tank It) and its outer end merginginto a reduced bore 24. A conical ball seat 25 is formed between theenlarged and reduced bores 23 and 24, respectively, and a ball 26 ispositioned in the enlarged bore 23 for the purpose of seating againstthe conical seat 25 and closing off the reduced bore 24 under certainconditions. A stop 21 prevents the ball 28 from becoming displacedentirely from the bore 23.

This arrangement of the ball valve fitting 22 is such as to permit flowof air through the fitting in either direction, but prevents the flow ofwater from the tank through the fitting into the conduit 2|. The latteris prevented by reason of the fact that the ball 28, in response to aflow of water from the tank through the fitting 22, rises against andseats upon the seat 25, thus closing off the reduced bore 24.

The air charger 11 provides a float chamber 28 in which is positioned a30 attached thereto by stem 3i for controlling the port 20. The stem 3|passes freely through an apertured plug 32 in the upper wall 33 of thefitting I9. The apertured plug 32 thus provides a guide for the valvestem 3 l.

The air charger I1 is further provided with an offset upper chamber 34,in the lower wall of which is positioned an air intake valve 35. The airvalve 35 includes a plug 36 having a small diameter bore 31 extendingtherethrough and terminating at its other end in a counterbore forreceiving a resilient seat 38. A ball valve 39 normally seats upon theseat 38. The valve 39 has a stem 40 passing through the bore 31 andterminating in an enlarged head 4| that projects beyond the plug 36.

The fitting l9 houses a Venturi-type eductor 42 having an intake nozzle43 for receiving water under pressure through the pipe l8 connected tothe discharge pipe H; of the pump II and a discharge nozzle 44 openinginto the interior 45 of the fitting IS. The eductor 42 is provided withan apertured, constricted throat 46 which is in communication with thefloat chamber 28 through a passage 41 in the upper wall of the fittingIS. The operation of the air charger illustrated in Figure 2 will now beexplained.

When the pump II is started, assuming the water level in the tank I!) tobe at or above the normal water level N, for instance, at the levelindicated by the reference character H, the ball check fitting 22prevents the flow of water through the piping 2! into the air charger H.The float chamber 28 is, however, filled with water from the end of theprevious cycle. Accordingly, the float 29 holds the valve 30 oil of itsseat 20 to permit the water in the float chamber 28 toserve as aprimefor the pump ll. As soon as the pump starts pumping, it creates asufficient suction in the intake l2 to open the foot valve l3 and drawin water through the intake supply pipe IS.

The water discharged from the pump through the discharge pipe 16 flowspartly into the tank In and partly through the piping l8 into theeductor 42. The reduced pressure at the throat 46 of the eductor 42causes water to be drawn from the float chamber 28 through the opening41, thus lowering the water level within the float chamber 28 andeffecting a reduction in the pressure above the water. Such reduction inpressure causes the air intake valve 35 to open and air to be drawn intothe offset chamber 34.

When the water level in the float chamber 28 had dropped sufliciently toallow the float control valve 29 to close the port 29, the continuedflow of water through the eductor 42 now flows through the throataperture 43, through the opening 4'! and into the float chamber 28. Thecontinued flow of water into the float chamber float 29 having a valve28 effects the displacement of the air therefrom into the tank It;through the piping 2i and the ball check valve fitting 22. The floatvalve 23 remains seated because of the difference in pressure betweenthat in the float chamber 28 and that in the pump intake piping !2.Water continues to flow from the throat of the eductor into the chamber28 until'pressures are balanced within the float chamber 23 and the tankIt, after which flow through the eductor ceases.

As soon as the pump stops, the foot valve 53 closes and pressure isequalized between the tank and the suction side of the pump through thepump itself, thereby permitting the float 29 again to rise and open theport 20. The charger is now ready to repeat the cycle when the pumpagain starts up.

If, however, the water level in the tank in slow the normal water level,as for instance, at the level indicated by the dot-dash line L, air ispreferentially drawn in through the check valve fitting 22 and thepiping 2| into the float chamber 28 and no atmospheric air is taken inthrough the air intake valve 35. The air so taken into the float chamber28 is displaced back into the tank l0 whenever the chamber 28 fills withwater, as when the pump stops or the valve 36 is seated. However, noatmospheric air is introduced into the tank l8 when the water level isbelow the normal water level.

f'hus, only when the pressure demand of the hydro-pneumatic tank Inrequires it is atmospheric air introduced into the tank through the airintake valve assembly 35.

It will thus be readily appreciated that the present inventioncontemplates the employment of a Venturi-type eductor for drawing in atmospheric air when the water level in the tan is at or above the normallevel, and the use of a float valve for controlling the flow of waterfrom the air charger to the intake side of the pump so that the eductorcan operate when the pump is operating to draw a flow charge of air intothe charger and subsequently effect the displacement of such air intothe hydro-pneumatic tank. Also, the air charger serves as a prime forthe pump because of its being positioned above the intake of the pumpand because of the arrangement whereby pressures equalize themselvesWithin the air charger and within the hydropneumatic tank and the aircharger fills up with water upon the pump being stopped.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claims.

I claim as my invention:

1. In a hydro-pneumatic system including a hydro-pneumatic tank and apump for supplymg water to the tank through a discharge line, an aircharger for supplying air to the tank in accordance with the level ofwater therein as maintained by the pump, said charger comprising acasing having an opening, a valve-con-- trolled connection from saidopening to the tank at about the normal water level therein to permitair flow through the opening in either direction and water flowtherethrough only in the direction of the tank, said casing having afluid flow opening for connection to the suction side of the pump, avalve-controlled air intake for admitting atmospheric air into saidcasing, an

aspirator having an inlet connected to the pump discharge line and anoutlet in flow communication with the pump intake line through saidfluid flow opening for connection to the suction side of the pump, saidaspirator having a conopening for connection to the suction side of thepump controlled by afloat in said casing, said valve being interposedbetween the discharge of said aspirator and the pump intake line,whereby provided the water level of the tank is above said normal waterlevel, when the pump is started up, said float-controlled valve being atthat time open, a flow of water under pressure through said aspiratordraws atmospheric air through said intake for introduction into thecasing and subsequent displacement therefrom into the tank through thevalve-controlled connection to the tank upon the further flow of waterinto said aspirator and through the vent in the throat portion into saidcasing.

2. In a hydro-pneumatic system including a hydro-pneumatic tank and apump for supplying Water to the tank, an air charger for supplying airto the tank in accordance with the level of Water therein as maintainedby the pump, said charger comprising a casing, a valve-controlledconnection from the casing to the tank at about the normal water leveltherein, the connection permitting air flow therethrough in eitherdirection and Water flow only in the direction of the tank, said casinghaving a fluid flow opening for connection to the suction side of thepump, a valve-controlled air intake for admitting atmospheric air intosaid casing, an aspirator receiving water under pressure directly fromsaid pump and discharging water into the intake side of said pumpthrough said fluid flow opening for connection to the suction side ofthe pump and having a constricted throat portion vented directly to theinterior of said casing for withdrawing water from said casing anddrawing air into said casing upon the flow of water through saidaspirator, and a float-controlled valve controlling said opening forconnection to the suc tion side of the pump controlled by a float insaid casing.

3. In a hydro-pneumatic system including a hydro-pneumatic tank and apump supplying water to the tank, an air charger for supplying air tothe tank in accordance with the level of water therein as maintained bysaid pump, said charger comprising a casing, a valve-controlledconnection from the casing to the tank at about the normal water leveltherein, the connection permitting air flow therethrough in eitherdirection and water flow only in the direction of the tank, said casinghaving a fluid flow opening for connection to the suction side of thepump, a valve-controlled air intake for admitting atmospheric air intosaid casing, a Venturi-type aspirator receiving water under pressuredirectly from said pump and discharging water into the intake side ofsaid pump through said fluid flow opening for connection to the suctionside of the pump and having a constricted throat portion vented directlyto the interior of said casing, and a float-controlled valve interposedbetween the discharge of the aspirator and the suction side of the pumpcontrolling fluid flow through said opening for connection to thesuction side of the pump Said valve being controlled by a float in saidcasing, said aspirator functioning, upon said float-controlled valvebeing open, to withdraw water from said casing and draw air into saidcasing and said aspirator functioning upon continued water flowtherethrough and the closing of said float-controlled valve, tointroduce water through its vented throat portion into the interior ofsaid casing to displace air into said tank through said valve-controlledconnection thereto.

4. In a hydro-pneumatic system including a hydro-pneumatic tank and apump for supplying Water to the tank through a discharge line, an aircharger for supplying air to. the tank in ac cordance with the waterlevel therein as maintained by said pump, said charger comprising acasing having a first opening, a valve-controlled connection from thefirst opening to the tank at about the normal water level therein, thevalve-controlled connection permitting air flow therethrough in eitherdirection of water flow only in the direction of said tank, said casinghaving a second fluid flow opening for connection to the pump intake, avalve-controlled air intake for admitting atmospheric air into thecasing, an aspirator having an inlet receiving water directly from thedischarge line of the pump and an outlet discharging water into thesuction side of the pump through said second fluid flow opening, saidaspirator also having a constricted throat portion vented directly intothe interior of said casing to cause atmospheric air to be drawn intothe casing upon water flow therethrough, a float-controlled valve insaid second fluid opening for controlling discharge of Water from theaspirator into the intake side of the pump and a float in said casingfor controlling said float-controlled valve, said casing being above thepump intake to provide a source of priming water for the pump.

5. In a hydro-pneumatic system including a hydro-pneumatic tank and apump for supplying water to the tank through a discharge line, an aircharger for supplying air to the tank in accordance with the water leveltherein as main tained by the pump, said charger comprising a casinghaving a first fluid flow opening, a valvecontrolled connection fromsaid first opening to the tank at about the normal water level thereinpermitting air flow therethrough in either direction and water flow onlyin the direction of the tank, said casing having a second flu flowopening for connection to the intake side of the pump, a valvecontrolled air intake, an aspirator connected directly to the dischargeline of the pump and discharging into said casing adjacent said secondflow opening, said aspirator having its low pressure throat zone ventedin direct flow communication with the interior of said casing, and afloat-controlled valve in said second fluid flow opening with its floatin said casing, whereby fluid flow through said aspirator will withdrawwater from the interior of said casing when said float-controlled valveis open, thus opening said air intake to replace water removed from thecasing with air and continued flow of water through the vented throat ofsaid aspirator when said valve is closed refilling the casing with waterand displacing air therefrom into the tank.

6. In a hydro-pneumatic system including a hydro-pneumatic tank, a pumpfor supplying water thereto, and a water supply pipe to said pump havinga foot valve therein, an air charger having a first fluid flow opening,a connection from the first fluid opening to the tank at about thenormal water level therein and a second fluid flow opening forconnection to the intake side of the pump, a check valve controlling theconnection from said first fluid opening to permit air flow in eitherdirection but preventing water flow from said tank to said charger, anair intake communicating with the interior of said charger, aVenturi-type aspirator having a vented constricted throat in directcommunication with the interior of said casing, said aspirator receivingwater directly from the discharge line of said pump and. dischargingwater to the intake side of said pump through said second fluid flowopening, a float-controlled valve controlling fluid flow through saidsecond fluid flow opening and interposed between the discharge of saidaspirator and the intake side of the pump, said aspirator withdrawingwater through its vented throat from the interior of said casing whensaid float-controlled valve is open and Water flow through saidaspirator is established, thus drawing air into the casing, and saidaspirator discharging water through its vented throat into the interiorof the casing, when said float-controlled valve is closed and water flowthrough the aspirator continues, to displace the air from the casinginto the tank through said first fluid flow opening.

ARTHUR W. BURKS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,172,057 Burks Sept. 5, 19392,172,097 Burks 1 Sept. 5, 1939 2,457,863 Burks Jan. 4, 1949 2,509,130Burks May 23, 1950

